Research On Active Clamping Soft-switching Wireless Charging System

In recent years,wireless power transfer(WPT)technology is more and more mature and widely used.At present,the WPT inverter circuits mainly include full bridge inverter circuit,half bridge inverter circuit and single switch LC inverter circuit.The first two circuits are suitable for high and medium power occasions,and have the advantages of mature scheme,but they use many switches and have low reliability.In the case of low power,single switch LC inverter is generally used.This circuit is inverted by a single switch,which has high reliability and is easy to realize soft switching,but the blocking voltage of the switch is high.In order to solve the above problems,an active clamp type soft switching circuit is proposed and designed based on the single switch LC resonant circuit,and the compensation network of the circuit is designed to realize the output independent of the load under the specific compensation network.The specific work of this paper is as follows:First of all,this paper analyzes the advantages and significance of WPT,summarizes the contributions made by universities,enterprises and scientific research institutes at home and abroad in this field,and summarizes the advantages and disadvantages of various inverter circuits used in WPT and their application occasions.Secondly,in view of the high blocking voltage of single switch LC inverter,an active clamp type soft switch circuit is proposed and compared with the original circuit.The structure and working principle of the new circuit are described in detail.Taking PS compensation as an example,the mutual inductance equivalent model of the circuit is modeled and analyzed,and the parameter calculation formula of each inductance and capacitance is given.In addition,the state equation of the circuit is listed,the different states of the circuit are analyzed quantitatively,and the blocking voltage of the switch is deduced emphatically.Then,the compensation network of the active clamp soft switching circuit is designed,and a CLCL-LCCL compensation network which can realize the output voltage and current independent of the load is proposed.The principle analysis and parameter calculation of this compensation network are carried out.Finally,the simulation and experiment of the active clamp soft switching circuit and the original single switch LC resonant circuit are carried out respectively.The constant current and constant voltage characteristics of the CLCL-LCCL compensation network are tested.The experimental results show that the blocking voltage of the proposed circuit is reduced by 42% and the cost is reduced by 17%.The feasibility of the active clamp soft switching circuit and the correctness of the compensation network parameter design are verified.